Transgenic Rice with Tolerance to Iron Deficiency in Soils

Although iron (Fe) deficiency is relatively rare in irrigated rice systems, it can lead to yield loss in alkaline or calcareous soils. Iron deficiency is the most difficult and expensive micronutrient deficiency to correct, as soil applications of inorganic iron fertilizers are often ineffective, except when application doses are large.

 Rice plants utilize the iron chelators (substances that bind particular ions removing them from a solution) known as mugineic acid family phytosiderophores (MAs) to acquire iron from the soil. Researchers at the University of Tokyo, the Japan Science and Technology Corporation, and the Japan Atomic Energy Research Institute, have transformed rice plants with a chelate-reductase gene from yeast, selected for its higher performance at high pH. The resulting transgenic plants have a higher tolerance to low levels of iron in the soil, manifested by an 8-fold increase in yield when compared to control plants.

The study shows that introducing genes encoding the enzymes in the biosynthetic pathway of MAs has the potential for engineering rice plants that are even more tolerant to low-Fe conditions, thereby having increased productivity in calcareous soils.

The open-access article, published in the journal PNAS, can be accessed at
http://www.pnas.org/cgi/reprint/104/18/7373